1. Field
The subject matter presented herein relates to detecting concealed objects in an obscuring medium and identifying material properties of the object using sub-millimeter wave (sub-MMW or SMMW) radio frequency (RF) and ultrasonic systems and methods.
2. Description of Related Art
Known techniques for locating and identifying concealed objects, such as contraband, explosives or hazardous material, when such concealed objects are located within an obscuring medium, such as clothing, can have limitations. Metal detectors can be ineffective in preventing some concealed objects from being detected, for example, if the objects are made of plastic or liquid materials.
Known systems using millimeter wave (MMW) frequencies can penetrate clothing, thus allowing the detection of hidden objects. However, MMW frequency bands below 100 GHz can have use restrictions, such as limited bandwidth availability to use in people screening applications for concealed objects. In addition, known MMW chips can have inherently narrow bandwidths. The narrow bandwidth can affect the quality of the MMW images and limit the ability to identify hidden objects.